Process of applying liquid coatings



7 July 21, 1925. 1,546,357

W. H. ALLEN PROCESS OF APPLYING LIQUID COATINGS Filed Aug. 6, 1924 I VENTOR BY (J mi 6i .TORNEY Patented July 21, 1925.

UNITED STATES WILL! H, ALLEN, OI DETROIT, IICEIGAN.

PROCESS OF APPLYING LIQUID COATIKGB.

Application fled August 6, 1824. Serial Io. 730,876.

To all whom it may concern:

Be it known that 1, WILLIAM H. ALLEN, a citizen of the United States, and residing at Detroit, in the county of Wayne and State of Michigan, have invented a new and Improved Process of Applying Liquid Coatings, of which the f0 lowing is a specification.

This invention relates to the application by spraying of lacquers, varnishes and other coatings which employ volatile solvents, and its object is to obviate the pebbly or uneven conditions of the resulting surfaces after the coating has dried, which unevenness necessitates expensive rubbin -down and olishing to produce the desire glossy sur ace.

When liquid lacquers, varnishes and similar coatings are sprayed upon the surfaces to be finished, a blast or constricted current of air carries fine particles of the liquid to the place where the coatin is to be applied. The liquid is usually ma e up of nitrocellulose or other derivative of cellulose, gums, or natural or synthetic resinous compounds, or mixtures thereof, used in making up varnishes and lacquers. These are dissolved in any of the volatile thinners such as ethyl, methyl, butyl and amyl alcohols or their derivatives, ketones, etc., neither the bases nor the solvents forming any part of this invention. Portions of the volatile solvents in some of these particles of liquid are taken up by the air of the air blast, which causes some of these particles to become partly dried out, so that when they impinge on the surfaces to be coated these particles do not flatten properly as do those particles which are in a more liquid state. The result is an uneven pebbly surface which must be rubbed down and polished to produce the desired glossy surface.

I have found that when the air emplo ed to produce a spray of this characteris rst saturated with the vapor of the solvent or the thinner as it is termed in the trade, this uneven eva oration of the particlesof the coating liquid does not take place and the particles of the liquid as they impinge upon the surface to be covered unite in a smooth ness and with a substantially flat and glossy coating of substantially even thicke surface which can be readily'polished, the pebbly effect being reduced to a minimum.

The saturation of the air with the solvent may accom lished in any desired manner, either be ore or after the air'is compressed, as by passlng it through the solvent 1n proper containers or through sprays of the solvent.

It is not actually necessary that the solvent of the coating liquid should be employed to saturate the air ofthe blast as any other volatile material may be employed whlch will be neutral to the solvent of the coating material, that is, will not aflfect it, and which will so saturate the air that it Wlll not take u any substantial amount of the solvent of t e lacquer or varnish.

The accompanying drawing illustrates means for carrying out this invention. The air brush 1 has a flexible hose 2 connecting it to the tank 3 which holds the coating to be sprayed. A reservoir 4 for the liquid A- with which the air is to be saturated 1s provided with a funnel 5 and a stop-cock 6 may be used to cut off the funnel from the contamer. A container 7 receives this liquid from the reservoir 4 by means of a pipe 8 which is also provided with a stop cock 9. The air forced by the blower 10 through the pipe 12 passes through the strainer 13 which reaks it up into small bubbles and these, in passing up through the liquid A are saturated therewith before passing out of the container and through the flexible tube 14 to the air brush 1. The depth of the liquid in the container 7 can be determined by the glass tube 15. The reservoir 4 may be replenished through the funnel 5, after which the stop-cock 6 is closed and the container 7 ma then be refilled by opening the stopcoc the device.

The details of this mechanism may all be changed by those skilled in the art without departing from the spirit ofmy invention as set forth. in the following claims.

1. The process of applying liquid coatings by spraym which consists in saturating the air emp 0 ed in the spraying with a solvent materia before bringing the air into 9 without stopping 'the operation of contact with the liquid to be sprayed, then mixing the air With the liquid to be sprayed, and applying the coating.

2. The process of applylng liquid lacquer, varnish and similar coatings by spraying, which consists in saturating air with a volatile material before bringing the air into contact with the liquid to be sprayed so that said air will not take up any substantial amount of said solvent from "the particles of the liquid to be sprayed, then 1nixing the air with the liquid to be applied, and then applying the liquid to the surface to be coated.

WILLIAM H. ALLEN. 

